issue 17992 Added extra params to message

pkg/shelf/test/request_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library shelf.request_test;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:shelf/shelf.dart';
 import 'package:unittest/unittest.dart';
 
-Request _request([Map<String, String> headers, Stream<List<int>> body]) {
+Request _request([Map<String, String> headers, Stream<List<int>> body,
+                  Map<String, Object> context]) {
   if (headers == null) headers = {};
   return new Request("/", "", "GET", "", "1.1", Uri.parse('http://localhost/'),
-      headers, body: body);
+      headers, body: body, context: context);
 }
 
 void main() {
   group("contentLength", () {
     test("is null without a content-length header", () {
       var request = _request();
       expect(request.contentLength, isNull);
     });
 
     test("comes from the content-length header", () {
@@ skipping 113 matching lines @@
         'content-type': 'text/plain; charset=fblthp'
       }).encoding, isNull);
     });
 
     test("comes from the content-type charset parameter", () {
       expect(_request({
         'content-type': 'text/plain; charset=iso-8859-1'
       }).encoding, equals(LATIN1));
     });
   });
+  
+  group("context", () {
+    test("are correctly populated", () {
+      expect(_request({
+        'content-type': 'text/plain'
+      }, null, {
+        'my-param' : 42
+      }).context['my-param'], equals(42));
+    });
+  });
 }